Exposure Therapy
by Splickedylit
Summary: Mike has a great idea to give his boyfriend positive associations when it comes to driving and going way too fast. Chuck can't believe he's going along with this, but in his defense, it's /Mike/. ((Established Muckles))


**Length:** 5,900 words

 **Characters/Pairings:** Mike/Chuck

 **Warnings:** light bondage, oral...obliquely-referenced sex toys, and dumb boys being fluffy at each other. b(UwU)d

 **Note:** I started writing this fic more than a year and a half ago and I never finished it until just now haha

* * *

Mike gives great boyfriend-presents.

He does! He really does, at least if the way Chuck smooches him after he brings one is any indication. He brings antique car parts, delicate pieces of circuitry rescued from dropped Kane Co. prototype bots, big dinners from all their favorite takeout places, and Chuck grins that grin that makes his eyes crinkle up under his bangs, flushes pleased pink and tilts Mike's face up to kiss him so thoroughly he gets dizzy.

Chuck's real good with his mouth. Mike never really thought about whether he would be or not, before they were…a thing…but even if he had, he wouldn't have imagined anything like this. Stuff like how Chuck's hands could take him apart like a circuitboard, how his mouth could make Mike unravel at the edges like a math problem, easy to solve and reduce to basic pieces and parts.

X=Mike's dick. Holy crap, he has got that one solved.

Anyway. Mike gives great presents. And he's pretty sure this one is going to go over great too, he just has to kinda…ease Chuck into it. If he'll just hear Mike out, he'll like it.

Mike's, like, 90% sure. It would be really great if Chuck liked it. He's totally gonna. Hopefully.

"Are you gift-wrapping stuff now, Mikey?" Chuck says, and turns the box over in his hands. Shakes it (it rattles just a bit, but not much). "Where did you get this?"

"The place that helped me make it does boxes." Holy crap, just walking in there had been embarrassing enough, he really doesn't want to discuss the process of buying this thing in too much detail. Mike rushes on. "You should just open it."

"Yeah yeah, I'm working on it." Chuck turns the box over one last time, admiring the old-fashioned black gift-box and the red ribbon, and then gets his nails under the ribbon and works it off. "Take it easy, dude."

"I hooked it up to Mutt's systems already," says Mike as Chuck works on the second ribbon, hurrying to get the explanation in before Chuck can see the box's contents and get too flustered to listen. "I haven't tested it out yet though."

Chuck opens the box and then stops dead, staring, slowly going scarlet.

"So," Mike continues, soldiering on even though it's really hard to think of words when Chuck's cheeks are flushing that amazing shade of red and his mouth is dropping open. "…the faster I go, the more—"

" _Fuck,_ " says Chuck, very quietly but with feeling.

"Dude," says Mike reproachfully. Then a second later, grinning irrepressibly, "—yeah though, basically. Thought maybe it'd help you. With my driving. Sounded like fun."

" _Fun_ ," repeats Chuck, faintly.

"Uh…yeah." Mike's smile falls a little. "…I mean, I thought—you don't have to."

Chuck groans and drags his hands down his face. "No—no, dude, don't look at me like that, it's—just kinda…wow. Uh…I don't…" he takes a deep breath. Another one, not looking Mike in the eyes. "I just…don't know what it would do to me. Geez."

Mike is smiling again. "You know I'll make sure it's good," he says, coaxing, and Chuck squeaks and goes red up to the tips of his ears. "We're gonna have to figure out a way to keep you from doing anything with your hands. Y'know, if you get…overwhelmed and junk."

" _Mike,_ " says Chuck weakly. "Holy crap."

"Every fifty miles per hour I speed up, it changes patterns," says Mike helpfully. "I put your favorite ones on the top speeds."

Chuck seems to be trying to crumple in on himself hard enough to remove himself from existence. " _You're crazy,_ " he mumbles, very high-pitched and shaky, hands pressed over his face. " _Oh my god, Mikey_."

"Yeah, but that's why you like me," says Mike, and grins when Chuck just groans at him. "Come on, Chuckles, have I ever lied to you about something like this? You'll be fine! I'll take care of you. Promise."

Chuck stays huddled in on himself, red to the shoulders and barely breathing, for a solid ten seconds. Then he shivers all over, takes a deep, deep breath and straightens up.

"…okay," he says weakly.

"Okay?"

"Okay," Chuck repeats, a little more confidently this time. "Okay, this is completely nuts, but you and your stupid face make me do crazy stuff all the time anyway. So why not."

"Don't sound to enthusiastic there, bud."

Chuck rolls his eyes, a familiar slight jerk of his head. "If I think about it I'm gonna freaking…pass out. Okay? Don't make me think about it, it's…I'm good, it's good, sounds fun. But don't make me think about it! Or I'll chicken out."

"Or…" Mike edges in. "I could distract you."

"Oh." Chuck blinks, and then bites his lip and grins. "…I'm…pretty hard to distract."

"I'll try hard then."

"Looks like you're already trying," says Chuck dryly, and oh, haha, dick joke. Got it. Yeah, this discussion's definitely starting up some boner action.

"Dang straight," says Mike, and pulls him in to demonstrate exactly how hard he's willing to try.

* * *

He kind of forgets about the little box and its contents after that. He's eager to try it out, he's pretty sure it'll be awesome-but Chuck needs some time to get his head around new stuff like this, and Mike is doing his best to work with that. And for a couple of weeks, he does. The Duke makes automaton versions of the Burners, and is furious when the Burners subsequently beat their artificial copies in a popularity contest. Chuck teaches Mike some of the…alternate applications of LARPing personas, which is a really awesome weekend that gives Mike a whole new set of things he didn't know he was into. Kaia tries to knock the whole team out with a forest of enormous mutant flowers Jacob calls "poppies", which rain sedative pollen.

So it's a pretty normal couple of weeks, all things considered.

It's a quiet night, a day or two after the most recent Kane attack, when the topic comes up again. Mike is in the garage tuning up Mutt in preparation to go out running errands, when he hears somebody coming into the garage behind him. The footsteps are faltering—not Texas. Not Julie, because if it was Julie then Mike would never hear her coming. Not Dutch, who Mike knows for sure is at the Cabler's Settlement. So that leaves...

"Hey buddy," says Mike, and worms a hand down into the depths of Mutt's back seat to pull out an old pizza-to-go box that somehow got jammed behind his seat. "I was gonna do some detail cleaning on our girl, but if you're ready to get outta here—"

"…yeah," says Chuck, and he sounds…weird. Kind of strangled. Mike stops in the middle of patting his bobblehead fondly, and frowns a little. What is that tone of voice? It sounds familiar, but he can't place it.

When he crawls backward out of the passenger's side door, dragging his trashbag, Chuck is standing behind him with his shoulders hunched. His face is pink, and he's standing all pulled-in and self-conscious, but other than that he looks totally okay. Just…nervous about something. Mike smiles, bemused but glad to see him, and Chuck bites his lip and rubs his arms, hugging himself like he's cold.

"…Chuckles? You okay?"

"I'm, uh." Chuck starts, then stops. Covers his face with both hands for a second. "… _geez…_ "

"Dude, seriously, are you okay? You're kinda freaking me out." Mike takes a step forward, reaching out; Chuck takes a step back and shivers. "Okay...talk to me bro. What's going on?"

"I'm…" Chuck opens his mouth, shuts it again, casts his eyes to the distant dome as if he's asking some deity to give him strength, and then finishes, with diplomatic slowness, "…I'm…using your present."

"My present?" Mike frowns for a second, confused, and then he sees Chuck shift his weight uncomfortably and the faint, pink flush to his cheeks and it clicks. Abruptly, it gets a lot hotter in the room. "My—oh. Oh, wow, dude."

"…you couldn't've…" Chuck shifts again—a sharp little jolt runs through him, jerking his hands—and makes the tiniest, almost inaudible sliver of a moan. " _Hh—_ y-you had to…pick something that was gonna… _geez_ , makes it…real, real hard to walk, dude."

Holy crap, what.

"What, you mean it's…" He makes a hand-gesture, crooks his fingers and imitates slow friction—Chuck's mouth twists up and he nods, cheeks flushed. "…holy crap. I didn't—wow."

"Yeah, like you didn't do it on purpose," Chuck says, accusatory but too weak to really sound angry. "Hhhhow—h-how am I supposed to walk anywhere. Seriously, what the heck."

"Totally a lucky accident," says Mike, "But yeah, you're right, I wish I did it on purpose. And you don't need to _walk_ anywhere, buddy." He leans back a little, and Chuck's eyes flicker to Mutt's gleaming chassis. His cheeks go even redder, and his breathing hitches. "…need a ride?"

" _Why do I let you talk me into stuff,_ " Chuck mumbles very softly, but there's a breathless whimper riding the words and he's already walking very carefully forward. Mike catches him on the way past, wraps an arm around his waist and pulls him in close to kiss him soundly. By the time he pulls away again, Chuck looks considerably more breathless and less skittish, albeit jittery with anticipatory nerves.

"We don't have to do it all today," Mike points out, softer now, and runs a palm over his boyfriend's hair, enjoying the way the untrimmed ends flips out through his fingers in an unruly fringe. "You can stop now, or—heck, dude, if it's hittin' you in all the right places maybe we _should_ leave it in for a while, let you walk around with—"

"If my legs go out," Chuck says, "—and one of the others wants to know why, I am going to _die._ " He pushes past Mike resolutely as Mike stares into the distance, briefly but intensely distracted by the idea of Chuck so turned on his legs give out in the middle of walking. Behind him he hears the door open, and turns in time to see Chuck swing himself inside with a sharp little shudder. "So, let's— _ah!_ Ah, jeez... _hff._ Come on, dude. We've got errands to run."

"Oh," says Mike, dazed. "Oh! Yeah, yeah. Right. Uh…before we go…"

Chuck stares at him when Mike leans in through his door instead of going to the driver's side—then he sees what Mike's holding and there's a flicker of movement like behind his bangs his eyes are going wide. "Oh my god," he says faintly. "You were serious."

"As the grave, Chuckles," says Mike, and winds the long strip of cloth from their bedside table around his hands, taking Chuck's wrists, easing them gently up over his head to the back of his seat. He leaves his grip loose, gentle, giving Chuck plenty of room to pull away—he shifts nervously in his seat, chews his lip, but doesn't resist as Mike wraps the cloth around his wrists with meticulous care and ties them to his headrest. "Relax. Seriously."

" _Relax,_ " Chuck repeats incredulously.

Mike grins at him. "Yeah," he says, and trails a hand down to tap Chuck's nose. " _Relax._ I got you, dude."

"Yeah," says Chuck just a little bit hysterically, as Mike buckles his seatbelts into place and closes his door for him. He works his wrists against Mike's knots as Mike comes around the car and swings into his own seat, and then takes a few hurried breaths, visibly forcing himself to go limp as Mike reaches out to find Mutt's ignition. "Yeah, right, okay—yeahhHAAHH—! Holy _shit_!"

"Okay?" Mike grins, and there's a hungry, wicked gleam in his eyes. "You ready?"

"You're _insane,_ " Chuck gasps, and squirms in his seat. His hands clench, pulling at the ties on his wrists—they hold. " _—mmh—_ "

"All you gotta do is tell me 'no', Chuckles."

Chuck chews on his lip, blushes to his shoulders and doesn't answer. Mike laughs to himself, leans in and steals a kiss. Then he sits back in the driver's seat and buckles in, pretending he's not looking as Chuck takes a couple of deep, fast breaths and slumps back against his seat. "…up to North Side," he says brightly. "Let's do it!"

He accelerates slowly the first time, way more slowly than usual, keeping half an eye on his passenger's seat; Chuck's breathing gets heavier and his hips occasionally twitch, but he seems to be working really hard to stay almost relaxed. And then Mike takes his foot off the gas and slows back down, and he closes his eyes and _moans_. Mike bites his lip on the answering groan that wants to come out, and glances over at him disingenuously instead.

"What's up, dude?" he says, and glances forward again—there's a broad stretch of flat road coming up. His foot hovers over the gas. "You okay?"

"Am I—?" Chuck starts incredulously, and then Mike punches the ignition and his voice immediately ratchets up to a high, breathless half-scream. "Nnh _ah_!—holy shit! Oh—my god, ohmygod…"

" _Geez, Chuckles,_ " Mike breathes, and shifts in his seat—reaches out, and hears Chuck make a terrible, wonderful little noise as he realizes what Mike is about to do. Mike shifts up six gears, and Chuck thrashes in his seat as the toy cycles rapidly from setting to setting, more and more intense and then resetting to a new pattern and then intensifying again. Changing gears with Mutt as Mike drives.

It occurs to Mike that that makes Chuck almost…a part of Mutt, something he's driving, a part of the whole machine, controlled with the same gears-and-gas controls he uses to control his car. And that should…that should _really_ not be as hot as it is. Holy crap though.

"I really wanna touch you right now, bro," he says, honest and breathless, and Chuck slumps in his seat as Mutt finally settles at the speed of 255. "I wanna—"

"Oh my god _oh my god MIKE LOOK OU—"_

Mike looks ahead just in time to see a familiar gap in the road. Mutt can make it easy, but not at 255—Mike punches the gas pedal and Chuck's scream cracks sharply into a whimper. His back arches up off the seat. Mike lands the jump while he's still panting and squirming—the _thud_ on the landing makes Chuck wince but with his eyes shut he can't see the way the car fishtails for a second before heading forward straight and true again. " _God,_ " he gasps, and slowly slumps back down as Mutt coasts and the muffled buzz dies down. " _Oohhhh god oh Mike oh god you're gonna kill me, bro—"_

Mike taps the accelerator a couple times, idly—every jolt makes Chuck twitch and jerk, throat working around choked noises. It's freaking adorable. "— _Mike—_ Mike—" He cuts off with a yelp as Mike jerks the wheel and drops abruptly from the road they're on to a parallel one ten feet down, but Mike immediately hits the gas and goes zooming off down the new road and Chuck is…distracted.

Mike happens to know off the top of his head that from 300 to 350 is a setting Chuck's especially… _fond_ of. It's a kind of rolling, irregular throb of vibration that builds slow and then pulses fast and then dies away again and gives him time to breathe—he cruises at 347, and listens to the pattern of rising moans and sharp whimpers from his passenger's seat.

"So," he says, and pulls up his map. He had it all laid out so they went from errand to errand the most direct way possible, but… "We got a consult with Rayon, and he needs something delivered. You feel up to discussing business right now, dude?"

"Oh my _god,_ " Chuck says, and then moans and pulls himself together enough to pant, " _Nnn_ o, n-no, don't let him _—_ "

"You're cool," says Mike, and Chuck groans when Mike reaches out, eyes still on the road, and runs a hand over his hair soothingly. "Bro, I was just joking. I'm not gonna let him see anything, I'll just talk to him from Mutt."

Rayon's motel isn't too far away—Mike lets his speed ease down a little, cruising. Chuck groans as the intensity dies down and down, and then yelps and jerks all over as Mutt hits 299 and he's abruptly dropped straight to the top intensity of the next setting down—sharp bursts of vibration like blaring alarm, one second on, two off, relentless. On and off, on and off. Chuck's breathing speeds up with the rhythm; a sharp, gasping inhale with every spell of rest, and then a trembling huff and a whine or a moan every time the vibe fires up again.

They're down to 35 mph by the time the Skylark Motel comes into sight in the distance, and Chuck has subsided into almost peaceful near-silence, cheeks red and eyes closed. Mike glances over at him a couple of times, and then he has to stop for a minute, put Mutt in idling park and turn in his seat. Chuck blinks at the sudden drop in speed, opens his eyes muzzily and then hums happily and leans into it as Mike kisses him and pets his sweaty hair.

The noises he makes get considerably less happy and more indignant when Mike leaves his mouth behind to suck on his neck and collarbones and play with his nipples through his shirt. But that's okay, because it's adorable when he gets into a swearing mood and his voice cracks and wobbles. Mike gets him fired up again, messes with him until he's annoyed and desperate enough to be awake, and then he sets Chuck's shirt back in order, wipes his sweaty face for him, kisses him one more time, and rolls Mutt into the Motel at a leisurely, torturously-slow pace.

Rayon is waiting for him—when Mike leans out the window to grin at him, Rayon lowers his glasses to give Mike's red cheeks and tousled hair a long, long look, but doesn't pry. If Rayon's anything, he's professional when it matters.

"Skylark Motel," he says off-handedly after negotiations are done and Mike is about to roll his window up. "…best place for a…night out. Rooms free to friends of the owner." He gives Mike a Look with a capital L. "…and soundproofed. Just in case you know anybody who might be interested." He turns his back, waving his dismissal. "…drive safe."

There are six more errands on the list, but one of them involves the Duke, which…no. And another one is a scavenging mission and would require them to get out and pick through the junkyards on foot, which would just be cruel at this point. Chuck doesn't look like he'd be able to walk even if Mike was in the mood to make him. So instead Mike shuttles back and forth across the spiraling roads of Motorcity—to the grocery store to deliver produce to Jacob from his hydroponic fields, to the lake to deliver the grounds-keeper a couple parts for his trawler, then back across the city to the Cablers' Settlement to return some specialist tools Dutch accidentally took home with him last time he visited. Chuck goes from squirming and irritated to breathless and rolling his hips desperately against nothing to lying back in his seat, groaning, twitching weakly whenever the vibrations get intense.

By the time they're two or three minutes' drive from the hideout, all errands done, he's barely coherent. Mutt smells like sweat and sex and is totally full of the sound of him groaning and whimpering for reasons that are _completely_ different from the normal ones, and it's _great._ The arousal and adrenaline rush feed on each other, and when Mike parks Mutt in an out-of-the-way corner of a deserted block near home and unbuckles to reach over a seat, the brief pressure of his belt across his hips is enough to make him suck in a sharp breath and tense up, groaning quietly.

That's nothing compared to Chuck though. Mike leans over to touch his face, and Chuck jerks and opens his eyes, hazy and almost black in the dark. He's making that noise that's kind of adorable and kind of scary—that tiny, utterly surrendering sound that makes Mike's chest tighten up. A soft, barely-audible sound on the back of every long, slow, trembling breath. There aren't words tender enough to describe it, so Mike doesn't try, just leans in and swallows the sound into a long, deep kiss.

" _…still doing okay?_ " he murmurs into Chuck's mouth, and Chuck whimpers very quietly and then rouses himself enough to bite petulantly at Mike's lip. "—ha! I know. Dude, you did so great. You did s— _mmhso good for me_ —that was awesome, you were _awesome_ —"

" _…_ you've got _two seconds,_ " Chuck rasps, hoarse and breathless. "—or 'm gonna—I know where you sleep, dammit _—fuck_!"

Mike almost laughs—considers briefly pulling away and pretending he's going to take another drive to see if it cleans out Chuck's mouth—but seriously. He's not a jerk.

" _Where do you get that dirty mouth from_?" He mumbles instead, and reaches down to work his fingers clumsily, wrong-handed, at the button of Chuck's jeans. They were already way too tight, even before the drive (have always been too tight, as long as Mike's been looking, and he's never quite learned to tune out the distraction). Yeah, that…that has to pinch a little. Chuck's breathing, already irregular and shaking, turns into deep, hungry gasps as he works the button loose and pops it open. " _…'s hot._ "

"Not _,_ " says Chuck, who seems to have regressed mostly to single-syllable words and noises. He's not wearing underwear—when Mike unzips his pants he lets out a gorgeous, shattered sound and slams his feet against the floor, twisting up desperately against the constricting seatbelt. Mike _hurts._ "Shut up! _Hurry_ up!"

"How do you want me to—"

" _Don't know don't care do_ something! Right now!"

"Yeah," says Mike, and can't hide the laugh on the words even when it makes Chuck glare at him. (His hair is sticking to his sweaty face, his cheeks are so red and there's involuntary tears in his eyes, it's so great, he's _so great…_ ) "Okay."

Just the feeling of Mike's breath is enough to have Chuck shuddering up against his belts, making a long, high keening sound in the back of his throat, and Mike takes a deep breath and lets himself go loose and…well. Swallows.

The downside to this whole experiment, Mike manages to think over the insistent ache of pleasure pounding up his spine-geez, and the unbelievable amount of filthy noise Chuck is making—the _downside_ to this is if Chuck's hands are tied over his head he can't reach down and do that thing he does. That thing where he pets tentatively at Mike's hair, scratches at his scalp and rubs the nape of his neck and behind his ears. And, maybe even better than any of those things, reaching down and yanking Mike around by the hair, giving up on words and just tugging his head wherever he wants it the most. Chuck 100% denies he does any such thing when Mike tries to bring it up but _god._ It's so good. He didn't even know he was into that until the first time it happened. That whole night had been…full of surprises.

He'd say all this to Chuck, too, if he didn't think stopping again now would give Chuck a heart attack. He rests a hand on one sharp hipbone instead, rubbing a thumb slowly back and forth as Chuck shakes and pants above him. The seat is sweaty and the air is hot and their skin sticks together when Mike slides an arm around and pulls himself closer, squirming around as the gear shift presses into his side, groaning soft and satisfied. It isn't comfortable, but that's fine. That's totally okay, he can deal with that for the way Chuck is coming utterly undone for him, falling apart at the seams. He was already a sweaty, panting mess, but now he's rapidly losing whatever coherency he has left, shoes scraping desperately at Mutt's interior as his legs jerk and twitch.

" _Mikemike_ mike _ohgod_ ," he yelps suddenly, and Mike grins for a second and then hastily stops as he feels his teeth come dangerously close to scraping. " _Mike,_ jeez—"

"Mm?" goes Mike, and Chuck _sobs_ and Mike shudders all over and moans, feeling mucles tense all over his body. Chuck's hips jerk up helplessly.

" _Stay,_ " he gasps. "Stay, s-stay there—nnh!" And if it's meant to be a plea it sounds a whole lot more like an order, and that thought abruptly supercharges all of Mike's nerves for a second. " _You can just—_ swallow _for all I—_ oh god _god_ mikeohmygod _fffuck—!"_

* * *

Chuck lies back in the seat and trembles, limp as a rag doll and eyes mostly closed, the rest of the drive home. Mike keeps his speed at 51—the lowest setting in the 50-100 range, a soft pulse that wrings shaking aftershocks out of Chuck for the rest of the short drive. They reach the hideout again, and Mike peers around the garage as they roll in—sweet. The other Burners' cars aren't there. They gotta be out.

" _Let's get you in bed,_ " he murmurs, and puts Mutt in park to finally turn off the engine. Chuck jerks in shock at the sudden loss of vibration, opens bleary eyes and groans. "Yeah, I gotcha. You don't hafta go anywhere, dude, I got it."

Chuck hisses between his teeth when Mike puts his clothes back in order, trying to be gentle on desperately oversensitive skin. His hips jerk once, weakly, like he can't decide if he wants to push into the touch or wince away. Mike doesn't make him pick. Pulls his shirt down and undoes his belt and the ties around Chuck's wrists, rubbing his hands gently to double-check circulation as Chuck slumps bonelessly down in his seat.

He's unwieldy to carry, but Mike kind of loves how he huddles in close and rests his head on Mike's shoulder, so he can handle the occasionally knee or elbow digging into him awkwardly. He scoops Chuck up, careful to avoid hitting his head on the doorframe, hefts his weight once to get a solid grip, and takes him to bed.

They've got a driving lesson tomorrow. Maybe if he's lucky, Chuck will let him borrow his present back again. Mike didn't mention it hooked up to Blonde Thunder's computers the same way it did to Mutt's, but…Chuck will figure it out. He's smart that way.

Mike gives great presents


End file.
